155. Min Stack

155. Min Stack

 code

class MinStack {
private:
    stack<int> s1;
    stack<int> s2;
public:
    /** initialize your data structure here. */
    MinStack() {
        
    }
    
    void push(int x) {
        if(s1.empty()||x<=getMin()) s2.push(x);
        s1.push(x);
    }
    
    void pop() {
        if(s1.top()==getMin()) s2.pop();
        s1.pop();
    }
    
    int top() {
        return s1.top();
    }
    
    int getMin() {
        return s2.top();
    }
};

/**
 * Your MinStack object will be instantiated and called as such:
 * MinStack obj = new MinStack();
 * obj.push(x);
 * obj.pop();
 * int param_3 = obj.top();
 * int param_4 = obj.getMin();
 */

 

 

 

1.

https://leetcode.com/problems/min-stack/description/